CMD: a blessing in disguise for Nigeria?

Improved variety cassava rootIITA

It is difficult to exaggerate the importance of cassava in Nigeria. The world's largest producer of this root crop, Nigeria is dependent on cassava as a daily staple but also as a vital subsistence crop for smallholder farmers in the south and central regions of the country. The crop also provides valuable commercial opportunities for farmers and small-scale food processors and, with its industrial potential, many - including the President - believe it could provide a vital boost to Nigeria's economic development. So the threat of a highly virulent form of cassava mosaic disease (CMD), spreading westwards from Uganda and resulting in severe crop losses, has been taken extremely seriously.

"Cassava mosaic disease is well known in Africa, and affects about half of the continent's cassava plants," says James Legg, a Uganda-based virologist who works jointly with the International Institute of Tropical Agriculture (IITA) and the UK's Natural Resources Institute (NRI). "African farmers have had to manage the disease for more than a century, but the situation suddenly worsened during the 1990s in Uganda when we detected a dramatic change in the aggressiveness of the disease."

The spreading pandemic

This 'super-disease' was caused by a chance recombination of two strains of the CMD virus, producing the so-called East Africa cassava mosaic virus-Uganda (EACMV-UG). Particularly severe symptoms were observed when this new virus and the previously known African cassava mosaic virus, ACMV, occurred together. Unusually high numbers of whiteflies - the vector of the disease - added to the problem, and the CMD pandemic was underway. Despite the deployment of resistant varieties and other control measures, the disease has continued to spread westwards. "The most recently affected areas are Burundi and eastern Gabon," says Legg. "There is a real threat to Nigeria."

In response to this threat, a unique pre-emptive project to protect Nigeria's cassava was launched by the Nigerian government and IITA in 2003, focusing on the 12 most vulnerable states in the south and southeast of the country. Replacing susceptible cassava plants with resistant varieties is critical, and participatory trials have been used to test potentially useful material. Five CMD-resistant varieties, which have also been selected to be high yielding and suitable for a variety of uses, are soon to be released and rapid multiplication and dissemination strategies are in place. Growing in farmers' fields, the resistant plants will form a critical defence, slowing the spread of the disease to non-resistant plants.

Boosting production and processing

But developing and disseminating resistant varieties is not the sole aim of this bold initiative. Mitigating the disease threat remains at the core of the project, which is currently due to run until 2006, but its overarching goals are broader and more ambitious. The project partners are also, for example, training farmers and processors, helping to set up processing factories, developing new, more efficient cassava-processing machinery and providing market information via a website, www.cassavabiz.org.

Peeling cassavaIITA

"We are collaborating with more than 50 organisations in Nigeria to build synergism and encourage anyone with a comparative advantage to move the cassava business forwards," says Richardson Okechukwu, an IITA-based scientist working on the project. "We have created great awareness on the potential of cassava as an industrial crop, livestock feed, and food crop. We encourage both public and private initiatives to join hands to revolutionise agriculture through cassava."

President Obasanjo believes that through such initiatives a 'cassava industrial revolution' could generate US$5 billion a year in cassava exports by 2007. His Presidential Initiative on Cassava, launched in 2002, is working towards this rather ambitious - although some say unattainable - goal. There seems little doubt, however, that cassava products - such as starch, flour and even ethanol - could find wider markets at home and outside Nigeria if production could be further increased while quality of products is maintained. As an example of policies to promote cassava, the government recently announced obligatory measures to include ten per cent cassava flour in bread-making - emphasising that the bread is more nutritious while its taste is unchanged, imports of wheat flour are reduced, and a market is created for cassava producers.

The current 'cassava fever' in Nigeria is happily not CMD, and the threat of that disease appears to be diminishing. But whether the farmers, processors, industries and government agencies can pull together to realise cassava's forecasted potential remains to be seen.